<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>二倍图</title>
    <style>
      /* 准备的图片是需要的图片的两倍 */
      div {
        width: 250px;
        height: 275px;
        background: url("../images/jpg/小熊.jpg") no-repeat;
        background-size: 250px auto;
      }
    </style>
</head>
<body>
    <div></div>
</body>
</html>